The Justice Ministry did not say how many inmates had escaped, but lawmaker Hakim al-Zamilisaid Monday that more than 500 fighters had gotten away.

A statement posted on radical Islamist websites and purporting to be from the Islamic State of Iraq and the Levant claimed responsibility for the attacks and said that “more than 500 of the best jihadi fighters” were among the freed inmates.

CNN could not confirm the authenticity of the statement, which was signed by the group’s Information Ministry instead of the more usual official media wing.

State-run TV Al Iraqiya reported that guards at Abu Ghraib, also known as Baghdad Central Prison, facilitated the prison break. Al Iraqiya ran part of an interview with Prime Minister Nuri al-Maliki, who said “the guards who were present inside the prison were part of this militia, they were complicit, and they are the ones who opened the prison gates.”

Al Iraqiya TV also reported that the Ministry of Interior had arrested a number of the escapees, but the report did not specify a number or from which prison they had escaped.